Over the years people have tried all sorts of techniques to attract BF to their campsite or camera trap.
However, I have never seen or heard evidence that any of these techniques work.
Most encounters are just random and not initiated by the witness (or researcher).
Some techniques that field researchers have used include:
1) Playing recorded sounds: animals in distress, baby crying, children playing, whale sounds, Sierra sounds recordings, Tibetan chants, native American music, new age music, etc.
2) Making BF-like sounds: howling, hooting, wood-knocking
3) Placing lights around camp: glow sticks, strobe lights, flashing colored lights, laser lights, etc.
4) Gifting: food, toys, crystals, natural oils/herbs, etc.
5) Pursuing activities that might interest BF: children playing, playing musical instruments, singing, cooking foods with strong smells, hiking at night, etc.
6) Placing odorants: hunting scent attractants, used tampons, pigs blood, etc.
I don’t think any of these techniques work, but the mythology of some of them working continues.
If any of these techniques was effective and reproducible, we would be having more frequent reports from same researchers and camera traps providing photographing evidence. Nonetheless, the field researchers that I know that have more than one encounter do not have any BF attracting technique. While their sighting occurred in a hot-spot, it was random and unexpected (not induced by any trick) and they were engaged in normal activities (hiking, camping, fishing, moving around camp).
Unfortunately, there is no formal database kept of research techniques tried and results. Even BFRO does not keep statistics on what worked well in their expeditions and what was the key to success (in those where a sighting took place).
In addition, there are some protocols/rules that are recommended to increase likelihood of BF encounter in a hotspot:
1) No usage of white lights (red lights only) at night
2) No guns
3) No dogs
4) No night vision or IR emitting instruments
It is also not clear if any of these rules increase the likelihood of an encounter or a BF moving closer to camp.
Most BFRO trips, follow these 4 rules. BFRO leaders probably developed these rules over time based on their experience.
The use of a campfire is not clear. There are cases where a BF approached the campfire (hiding behind trees) to check on the campers. On the other hand, some researchers say that the fire light bothers them and that they will get closer to camp without a fire (similar logic as the red light vs. white light).
I was in a BFRO expedition in WA, where two guys used technique #5 above (playing harmonica and singing), and they got to see part of a BF (hand and glowing red eye) from a creature that approached them on the ground behind a log). But the technique has been tried again by others and was not reproducible. For an encounter, you certainly need BF presence but also the creature needs be curious and maybe inexperienced (testing their skills). Otherwise, why approach humans in a campground?